Economizer



July 13,1926. 1,591,975 v l L.. J. HEATH EcoNQM-IZER Filed Feb. 28. 1924 Patented july i3, i926.

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LESLIE JOHN HEATH, OF CAMBRIDGE, MASSACHUSETTS, ASSIGNOR TO IB. F. STURTE- VANT COMPANY, 0F HYDE PARK, MASSACHUSETTS, A CORPORATION 0F MASSA- CH'USETTS. Y

ECONOMZER.

Applzication led February 28, 1924. Serial No. 695,843.

The present invention relates to fuel economizers and more particularly to econoinizers designed for withstanding high internal pressures.

Fuel economizers are at present commonly constructed of cast-iron, both headers and tubes being of this material. With the increase in pressures under which such devices are now requiredto operate it has been pioposedto use steel in the place of castyiron in order to secure increased strength, and while the tubes may be very conveniently formed from seamless tubing, difficulty has been experienced in providing headers of this material inasmuch as the wall of tubing is ordinarily too thin to hold the tubes with the necessary rigidity.

The yobject, of the present invention is to -provide an economizer of steel construe tion which has ample strength to withstand the usual modern high pressure conditions, which possesses the requisite rigidity, which is of no greater outside dimensions than those now employed` for lower pressures, and ,which can' be manufactured at relatively low' cost.

With these objects in view the invention Y contemplates a construction of economizer having Vsteel tubes and a header formed with a central steel tube about which is cast a body of metal. The central tube 'of steel provides the necessary strength to resist the highinternal pressure, while the surrounding body ofrcast-metal serves primarily to supp-ort the steel tubes and to provide bearing surfaces of sufficient length axially of Vsuch tubes to Vinsure a strong and rigid structure.

In the accompanying drawings Fig. 1 is a vertical sectional elevation of an econoniizer section embodying top and bottom tubes 6 in parallel, and thence through the 4outlet header from which it may lead into saine strength as the parallel econoinizer tubes, enev end of the tube 10 being closed by a initered cap V12 which is welded to the tube. While the tube 10 may be of any desired shape, it is preferred to use the square form as illustrated in the drawings in order to facilitate the securing of a good joint between such header tube and the Vecono-v rnizer tubes without protrusion of the tubes into. the interior of the header, thus maintaining a practically unobstructed passage through the header. In order to provide for external connections a round seamless tube 14 is welded yat 16 to the square tube 10,Y the welded end of the round tube being compressed at 18 to form a square end which butts against the end of the square tube 10. The header tube is preferably provided at this stage with the openings in its bottom for receiving the economizei` tubes and with aligned openings of slightly larger size in its top through which the tubes are t-o be inserted.

The header tube thus formed is then placed in a mold and a body of iron 20 is cast about the steel tube, brackets 22 and 24 being formed for supporting the header 1n any convenient manner. By means of suitable. cores, the cast-iron body is provided with openings for receiving the tubes 6 Yand also with tube inserting openings 26 registering with the corresponding openings in the header tube 10. It has been found that the presence of the cold steel tube in the mold causes no difficulties either in the pouring of the iron or in the subsequent cooling thereof, the steel tubing being irinly retained within the cast-iron body without appreciable stresses due to shrinkage.

After the casting, the several openings in the cast-iron body and in the header tube areinachined to size, and the economizer tubes 6 are inserted, from the upper side through the openings 26. The tube receiving openings in the header are machined at 32 with substantially parallel sides, each tube being provided at its upper end With an enlarged portion 3l which tapers inwardly to a slight degree from top to bottom to provide a tight, steel to steel jouit vrith the header tube. The Contact betvveen the upper end of the tubes and the surrounding body of cast-iron, as at 35, While not necessarily steam or water tight is sutiiciently close to furnish a firm support for the tubes and to impart the necessary strength and rigidity to the structure. rl"he tubes are provided at their top ends with flanges 30 'which seat against the inner face of the tube l when the tube is forced to its iinal position.

The tube inserting openings 26 are made slightly larger than the diameter of the iianges and are machined at 36 with a taper to receive tapered plugs 38. The plugs are inserted into the header through the outlet opening and after being drawn into the openings 2G are secured in position by caps 4D and bolts l2. The iluid pressure during normal operation also acts to seat the plugs tightly Within the openings to prevent any leakage.

The lo\ ver o1' inlet header 4e is similar in construction to the upper or outlet header 8, and comprises a square seamless steel tubing la closed at one end by a Welded initered cap 16Y and Welded at the other end to a round inlet tube 48, the Whole being surrounded by a body of cast-iron 50. The header tube and its cast-iron body are provided with onlyone series of openings, viz, the tube receiving openings 52 which are tapered to engage tightly with the tapered lou'er ends of the tubes G. Here again it is the steel to steel joint between the header tube and the economizer tube Which is relied upon to prevent leakage of steam or Water, the contact of lthe adjacent body of cast-iron with the end of the tube being for the purpose of securing rigidity and strength in the structure. The header 4 also has 'a supporting bracket 54: similar to the brackets for the header 8.

A complete economize'r section comprises the headers 4- and S, together with a plurality of economizer tubes 6, ordinarily ranging from six to eighteen tubes in the usual construction. In operation t-he boiler feed Water passes successively through the header 4, tubes G and header 8. A number of exactly similar economizer sections are usuallv provided, connections being made between the headers in any convenient manner so that the Water may circulate either in series or parallel through the sections. All of the sections are included Within a casing through which hot flue gases are passed in contact with the economizer for preheating the feed Water. I v

It ivill be seen that the central steel header tubes, being of the same material and of substantially the same strength as the ecouomizer tubes, are not liable to rupture under any pressures which may safely be used on the economizer tubes. The header derives practically its entire strength from the interior steel tubing, the cast-iron body serving to support the central steel tube and hold it rigid and to provide a long bearing joint for each economizer tube so as to hold the latter rigidly in place. The castiron body7 also strengthens the Welds between the portions of the steel tubing and provides convenient means for mounting the headers. lt also cooperates and assists in the proper positioning and fastening of the closure plugs.

Although the invention is herein illustrated and described in a specific form of fuel economizers, it will be understood that the invention is not necessarily limited thereto but may be employed in other analogous constructions and the forms and pro portions of the parts may be varied as desired. Where in the claims the term economizer is employed, this is to be taken to mean any analogous structure.

Having thus described the invention, what is claimed is l. An econoniizer or the like comprising a pair of separate headers and a pluralit' of steel tubes connecting the same, eaci header| having a central steel tube to which the tirst mentioned steel tubes are connected and an enclosing body of cast-metal which surrounds each of the connecting tubes adjacent its end to support the headers and tubes in rigid relation.

2. An economizer or the like comprising a pair of separate headers each having a central tube provided with tube receiving openings and a body of cast-metal surrounding the tube, and econoinizer tubes entering the tube openings with a tight fit and having supporting contact with the cast-metal body to hold the headers and tubes in rigid relation.

3. An ec'onoinizer or 'the like comprising separate headers each 'consisting of a thin steel tube surrounded by a thick body of cast metal and having openings in the tube and metal to receive the ends of the econonii'zer tubes, and ecouomizer tubes fitted Within the openings and engaging the header tubes with a tight taper lit and having supporting contact with the castv metal to hold the headers and tubes in rigid relation.

i. An economizer or the like comprising a header having a substantially square tube provided With tube receiving openings on one side vand tube inserting openings aligned therewith on the opposite side, a body of cast metal surrounding the tube and having openings registering with the openings therein, economizer tubes adapted to pass through the tube inserting openings and with a flange on the following end to en-l comprising a thin central steel tube having gage the inner Vface of the header tube, the an opening for receiving an economizer tube, end of the economizer tube making a tight and a thick body of cast-iron surrounding 1o joint with the header tube, and being supthe tube and the opening to provide a supported by the body` of cast metal, and elo-` port for the end of the econoniizer tube to sures for the tube inserting openings. hold the tube and header in rigid relation. 5. A. header for economzers and the like 'LESLIE J. HEATH. 

